diff --git a/apps/web/src/components/Sidebar.tsx b/apps/web/src/components/Sidebar.tsx
index d863e285a80e7..7327521ecf527 100644
--- a/apps/web/src/components/Sidebar.tsx
+++ b/apps/web/src/components/Sidebar.tsx
@@ -360,6 +360,10 @@ interface SidebarThreadPartitionInput {
   readonly clockKey: string;
 }
 
+function isPlatformModKey(event: { readonly metaKey: boolean; readonly ctrlKey: boolean }) {
+  return isMacPlatform(navigator.platform) ? event.metaKey : event.ctrlKey;
+}
+
 function scrollSidebarToTop(content: HTMLElement | null) {
   content?.closest("[data-slot=scroll-area-viewport]")?.scrollTo({ top: 0 });
 }
@@ -1556,10 +1560,8 @@ export default function Sidebar({ routeReveal }: { routeReveal: SidebarRouteReve
 
   const handleThreadClick = (event: ReactMouseEvent, threadRef: ScopedThreadRef) => {
     if (isSidebarNestedLinkClick(event.target)) return;
-    const isMac = isMacPlatform(navigator.platform);
-    const isModClick = isMac ? event.metaKey : event.ctrlKey;
     const threadKey = scopedThreadKey(threadRef);
-    if (isModClick) {
+    if (isPlatformModKey(event)) {
       event.preventDefault();
       toggleThreadSelection(threadKey);
       return;
@@ -3019,7 +3021,7 @@ export default function Sidebar({ routeReveal }: { routeReveal: SidebarRouteReve
                       setProjectScopeKeys([]);
                     } else if (
                       eventDetails.event instanceof MouseEvent &&
-                      eventDetails.event.shiftKey
+                      isPlatformModKey(eventDetails.event)
                     ) {
                       // Canceling skips Base UI's commit, which would freeze the search query, and its close.
                       eventDetails.cancel();
@@ -3095,13 +3097,18 @@ export default function Sidebar({ routeReveal }: { routeReveal: SidebarRouteReve
                           toggleProjectGroupPin(project);
                           return;
                         }
-                        if (event.ctrlKey || event.altKey || event.metaKey) return;
-                        if (event.shiftKey && event.key === "Enter") {
+                        if (
+                          event.key === "Enter" &&
+                          !event.shiftKey &&
+                          !event.altKey &&
+                          isPlatformModKey(event)
+                        ) {
                           if (!project) return;
                           event.preventDefault();
                           toggleProjectScopeKey(project.projectKey);
                           return;
                         }
+                        if (event.ctrlKey || event.altKey || event.metaKey) return;
                         if (
                           event.key !== "ContextMenu" &&
                           !(event.shiftKey && event.key === "F10")
diff --git a/docs/user/thread-sidebar.md b/docs/user/thread-sidebar.md
index f5ea773067e89..974182be944e5 100644
--- a/docs/user/thread-sidebar.md
+++ b/docs/user/thread-sidebar.md
@@ -232,6 +232,11 @@ On mobile, the thread list search also lists message matches and opens them at
 the matching message; on an iPad with a keyboard, `Cmd+K` opens the same
 palette.
 
+On web and desktop, the project filter at the top of the sidebar narrows the thread
+list. Pick a project to show only its threads, or `Cmd/Ctrl+click` it (`Cmd/Ctrl+Enter`
+from the keyboard) to add or remove it and keep the menu open. On mobile, the filter
+holds one project.
+
 Use **Settings → Keybindings** to find or customize shortcuts for searching files
 and copying a thread reference. A copied reference uses the thread's pull request
 link when available, otherwise a link to the thread, which opens it from anywhere